Refillable fuse.



B. L. SPURR & F. A. TITTEMORE.

REFILLABLE FUSE. I

APPLICATIUN FILED Amzr, 1916.

1,257,418. Patented Feb. 26, 1918.

7 E5 .5. WITNESS J- 8 z'gv FNTORS W Q 42m. @Wifi ATTORNEYS Fig. 3 is a transverse section taken-in the I BASIL Ia. AND FRANK A. TITTEMOBE, OF'RICHMOND, CALIFOBNEA.

REFILLABLE FUSE.

Specification of Letters Patent.

Patented Feb. 26, 1918.

Application filed April 27, 1916. Serial No. 94,000.

To all whom it may concern:

Be it known that we, BASIL L. SPURR and FRANK A. TITTEMORE, citizens of the United States, residing at Richmond, in the county of Contra Costa and State of California, have invented certain new and useful Improvements in Refillable Fuses, of which the following is a specification.

The present invention relates to electric fuses of the inclosed or cartridge type, and more particularly to a fuse cartrid e, the fusible element of which can be rea ily removed and replaced.

Refillable fuse cartridges, as heretofore constructed, have been open to a serious objection; namely that the fusible element may be replaced with one of greater capacity than the original, without such substitution being apparent, since only the outside, or permanent portions of the cartridge, are marked with the rated capacity of the fuse. Thus, by the substitution of a fusible element of greater capacity than that for which the shell is rated, the laws and regulations prescribing the capacity of fuses in relation to the equipment which they are intended to protect may be set at naught, either through ignorance or malicious intention, with very little probability of detection.

By the present invention, however,this objection is overcome, sincea fusible element of the rated and proper capacity only can be installed within a given'cartrid e.

The object of the present invention, t erefore, is to provide a fuse cartrid e whose fusible element can be quicklyv an cheaply replaced, and in which a fusible element of the proper capacity only ma be installed.

In order to comprehend the invention, reference should be had to the accompanyini drawings, whereinigure 1 is a lon 'tudinal section through the center of the v I Fig. 2 is a transverse section taken in the direction of the arrows on the line 2-2 of direction of the arrows on the line 3-3 of Fig. 1. I

ig. 4 is a transverse section taken in the direction of the arrows on the line 4-4 of 13 ,1,-

Fig. 5 is a'transverse section taken in the g i rection of the arrows on the line 55 of In the drawings, the reference numeral 1 designates an insulatin shell, formed preferably of compressed ber or other similar material, and provided with a refractory lining 2, preferably of asbestos. The ends of the shell 1 are exteriorly threaded, as shown at 3 and 4,, and a pair of longitudinal sockets 5jand 6 are formed between the shell 1 and the lining 2, extending inwardly from each end. Reinforcing collars 7 and 8, preferably metal, are placed between the shell and the lining, and are formed with grooves 'in their sides, as shown particularly in Fig.

5, to partially embrace said sockets 5 and 6.

At one end of the fuse is a contact member 9, herein shown as having a flat exterior blade, although it is to be understood that any form of exterior contacting and supporting member may be employed. The inner portion of the contact blade 9. is formed with a pair of spaced parallel prongs 10, adapted to lie within the sockets 5 of the shell, to prevent said contact member from turning. v

The contact member 9 is retained in position by means of lugs 11 projecting from the edges thereof, said lugs lying under a slotted the prongs 10, is an extension 14, to which is permanently attached, by a rivet or solder, a fusible element 15, here shown as a flat metallic strip. s A

A the other end of the shell is a secon contact member 16, having inwardly projecting prongs 17 adaptedto lie within the sockets6, said contact member lfi'being held in position by l 18, an end closing cap 19, and a screw co r 20, in-amanner similar to that described above in reference j to the contact member 9. Said'second con-' tact member 16 carries, between the prongs upon the end of the shell 1 by the screw 17, a pro'ecting In 21 preferabl hemispherical in form, as shoivn in Fig. 1: The end clos' formed w1th ventilatin apertures 12 and 19, to allow a free .circ ation of air throu h the the shell 1 andarouhd the fusible ement 15 to minimize overheating of the same under normal conditions.

A late 22, preferably dished as illustra lies transversely across the end of the lining 2 within the reinforcing collar 8. This plate is formed with an aperture 23, corresponding very closel inrshape and size to the cross section 0 the end portion of the fusible strip 15. Said end portion 5 of the fusible strip is preferabl split, as at 24, and the two parts thus ormed are bent over, as at 25, after being passed through the aperture 23 in the plate 22, as shown in Fig. 8, so that the end of the fusible strip is thus securely supported by the plate 22. The projecting lug 21 of the contact member 16 makes electrical contact with the bent over ends 25 of the fusible stri 15 when said contact member 16 is forced own collar 20. l l

Thus it will readily be seen that in order to remove the fusible element 15, it is only necessary to unscrew the end collars 13 and 20, and release the ends 25 of the fusible strip from their bent-over engagement with the apertured plate 22. The contact member 9 with the fusible element 15 may then be withdrawn and a new contact member and fusible element inserted in its place. If the fuse be melted as .would usually be the case, one portion thereof comes out with the contact member 9, and the other portion may be readily withdrawn from the other end of the shell by removing the plate 22.

and the portion of fuse connected therewith. "The contact member 9 being permanently attached to the fusible element 15, the capacity of said fusible element can be stamped or otherwise marked exteriorl upon said'contact member; and by provid ing a contact member of a different size or shape for each size of fusible element, only .a fusible element of the proper capacity can be inserted in a given shell. Moreover, the fusible element must pass through the aperture 23in the plate 22, so that with a given plate, the size of the fuse is positively.

limited by the size of the. aperture in said plate; and by correlating the exterior diameter of the late 22 wlth the size of the aperture 23 t erein, an additional and efiec- 'tual check is rovided against the possibility of the use 0 a fusible element of ter capacity than that for which the ell 1s caps 12 and 19 are preferably Letters Patent is:-

having 'a longitudinal socket form contact member in position.

-tached to said contact mem broadly as the state of the art will permit.

Having thus described our invent1on,what we claim as new and desire to protect by 1. An inclosed electric fuse comprising a substantially ylindrical insulati shell 23 in its wall and extending inwardly from its end; a contact member removably associated with the end of said shell; an extension carried by said contact member and adapted to lie within said socket to prevent the rotation of said contact member; a second contact said shell; and a fusible metallic element within said shell, each end of said fusible element having electrical connection with one of said contact members.

2. 'An inclosed electric fuse comprisin a substantially cylindrical insulating s ell having an exteriorly threaded portion at member associated with the other end of each end; a contact member adapted to form va closure for one end of said shell; a screw collar for holding said contact member in position; a fusible metallic element having one end attached to said contact member and projectin inwardly therefrom; a plate transversely isposed within said shell, said plate having an aperture for receiving and holding the free end of said fusible element; a second contact member forming a closure for the other end of said' shell and having electrical connection with the end of 'sai fusible element held by said plate; and a second screw collar for holding said second 3. An inclosed electric fuse comprisin a substantially cylindrical insulating ell having an exteriorly threaded ortion at each end; a pair of contact mem rs formin closures for the ends of said shell screw cofiars for holding said contact members in 'positlon; means for preventing the rotation ct to said of said contact members with respe shell; an apertured'plate transversely. dis posed within said she 1 near one end thereof and a fusible metallic element one end thereof being permanently attachedtoone of said contactunembers and the other end pass" throughfthe'aperture in said plate, and hem removably attached thereto and havin ectrical connection with the other of sai contact members.

4.-,An inclosed electrical fuse comprising shell/a contact. member for 1tting over one end thereof, a fusiblemetal- 1c element having one end ing inwardly therefrom, a late transversely disposed within said she said plate having an aperture for receiving and holding lpeermanently.atr and. project the free end of said fusible element, a second contact member for fitting ever the other end of said shell and havin electrical connectionwith the end of said usible element held by said plate, and means for holding said contact members in position over the ends of said shell.

In testimony whereof we have signed our names to this specification in the presence of a. subscribing witness.

BASIL L. SPURR. FRANK A. TITTEMORE. Witness: HARRY A. TOT'I'EN. 

